[special-K]

You need motivation?You probably won`t be able to replace it as easy as to keep it.
You know,I think slappin` overdrive in these old trucks is over rated.I mean,If you can do it cheap(rare)and have the time,then great!But,all you need to do is slow down to where these things really want to cruise and you`ll get the same mileage as with that o/d you spent all your gas money on.I`m just saying the best way to save money is don`t spend it.
I`d never put a 700r4 in a truck w/o a rebuild and upgrades.Even if the trans was free,it`s a good bit of money.They don`t hold up like the good ol`TurboHydramatics,either.I`d love to have o/d,but run just fine without.
Same thing with gears.If you drive the speed the gears are happy at,you`ll get the mpg.If your rear needs rebuilt,heck yes,slap a higher set in there.But,I don`t spend gas money on gears,either.
It comes down to,it costs alot to drive these trucks as fast as modern trucks,which ain`t that cheap.Not just to drive them.